(x^2-2x+1/x2-1)/(x-1/x^2+x)-x
=[(x-1)^2/(x+1)(x-1)]/[x-1/x(x+1)]-x
=x-x=0
原式值=0与x无关
无论x取何值,代数式值恒为0“=[(x-1)^2/(x+1)(x-1)]/[x-1/x(x+1)]-x=x-x”这个是怎么的出来的啊？[(x-1)^2/(x+1)(x-1)]/[x-1/x(x+1)]-x=[(x-1)^2/(x+1)(x-1)]*[x(x+1)/x-1]-x=x(x-1)^2*(x+1)/(x+1)(x-1)(x-1)-x=x-x=0